How to calculate and use new direction angle as a new forward direction.

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1

My player is a cube tumbling forward/backward and sideways.

This script calculates the edges of my cube and make it rotate around its edge.

void FixedUpdate()
        {
            bound = GetComponent<BoxCollider>().bounds;

            left = new Vector3(-bound.size.x / 2, -bound.size.y / 2, 0);
            right = new Vector3(bound.size.x / 2, -bound.size.y / 2, 0);
            up = new Vector3(0, -bound.size.y / 2, bound.size.z / 2);
            down = new Vector3(0, -bound.size.y / 2, -bound.size.z / 2);

//These are the ‘positionToRotations’ when pressed by arrows)
}

        IEnumerator Roll(Vector3 positionToRotation)
        {
            isRolling = true;

            float angle = 0.0f;
            Vector3 point = transform.position + positionToRotation;
            Vector3 axis = Vector3.Cross(Vector3.up, positionToRotation);

            while (angle < 90f)
            {
                float angleSpeed = Time.deltaTime + rotationSpeed;
                transform.RotateAround(point, axis, angleSpeed);
                angle += angleSpeed;
                yield return null;
            }
            transform.RotateAround(point, axis, 90 - angle); 
            isRolling = false;
        }

(What I like about this function is that I can change the size of the cube and make it a rectangle too)

But when my cube is randomly rotated (Y axis) in the world space, it tries the find the wrong ‘point’ and ‘axis’. So I need to calculate where these are and (even more complicated for me) write a line how to use them.
This picture illustrates what I’m stuck at.

182777-schermafbeelding-2021-06-29-om-144008.png
182777-schermafbeelding-2021-06-29-om-144008.png1278×1470 141 KB

I have no idea how this works in the mathematical way. I tried a lot of Quaternion.AngleAxis stuff, but I don’t fully understand the math behind it.

2

Well, since I figured out how this works, I’d just answer it myself for everyone who might encounter this post in the future…

This is how it works

     IEnumerator Roll(Vector3 positionToRotation)
        {
            isRolling = true;
    
            //GroundLevel
            RaycastHit hit;
            Physics.Raycast(thisRigidBody.position, Vector3.down, out hit);
    
            //RB gravity
            thisRigidBody.useGravity = false;
    
            Vector3 cam = Camera.main.transform.forward; cam.y = 0;
    
            float angle = 0.0f;
            //This calculates the perpendicular of the cam forward
            float angleNeeded = Mathf.Atan2(Vector3.Dot(Vector3.up, Vector3.Cross(newUp, cam)), Vector3.Dot(newUp, cam)) * Mathf.Rad2Deg;
            
    Vector3 point = transform.position + positionToRotation; 
            Vector3 groundPoint = new Vector3(point.x, hit.point.y, point.z);
    
            Vector3 axis = Vector3.Cross(Vector3.up, positionToRotation);
            Vector3 camAxis = Quaternion.AngleAxis(angleNeeded, Vector3.up) * axis;
    
            while (angle < 90f)
            {
                float angleSpeed = Time.deltaTime + rotationSpeed;
                transform.RotateAround(groundPoint, camAxis, angleSpeed);
                angle += angleSpeed;
                yield return null;
            }
            transform.RotateAround(groundPoint, camAxis, 90 - angle);
    
            thisRigidBody.useGravity = true;
            isRolling = false;
        }